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Inversion of Nitrogen Content in Winter Wheat Based on Unmanned Aerial Vehicle Hyperspectral Fractional Differentiation

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Journal of engineering Science and technology Review 2023年第4期16卷 153-170页

作者： Xiaoxiao, Ma Peng, Chen Changchun, Li Yingying, Cui Van Cranenbroeck, Joël School of Civil Engineering and Architecture Zhengzhou Vocational University of Information and Technology Zhengzhou450046 China Henan Province Engineering Research Center of Intelligent Green Construction Zhengzhou45004 China Xiangcheng City Planning Technology and Exhibition Center Zhoukou466200 China School of Surveying and Land Information Engineering Henan Polytechnic University Jiaozuo454003 China 5530 Belgium

Crop nitrogen content inversion based on UAV (Unmanned Aerial Vehicle) hyperspectral data is vital for addressing global food supply challenges. Many studies have estimated nitrogen content via simple linear regression using a single vegetation index, multiple vegetation indices, hyperspectral representation, and simple structural transformation. Utilizing UAV hyperspectral data of the winter wheat canopy and leveraging the benefits of fractional differential processing to enhance spectral details, traditional hyperspectral vegetation indices were established, and characteristic parameters derived from spectral position and canopy area were extracted. Then, winter wheat plant nitrogen content models with different spectral information characteristics were highlighted, optimally selected and verified. Results reveal that when the original canopy spectrum is processed using the fractional differential, the association between hyperspectral reflectance and nitrogen levels in winter wheat plants can be effectively enhanced. Fractional differential spectra represent outstanding effects on refining spectral details. The findings provide valuable insights into the potential of hyperspectral fractional differential spectra to enhance the precision of nitrogen estimation in winter wheat. © 2023 School of Science, IHU. All rights reserved.

关键词： Food supply

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Property estimation of free-field sand in 1-g shaking table tests

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Earthquake engineering and engineering Vibration 2022年第3期21卷 591-604页

作者： Xu Chengshun Jiang Zhiwei Du Xiuli Deng Lijun Li Zheng College of Architecture and Civil Engineering Beijing University of TechnologyBeijing 100124China National Engineering Research Center of Green&Safe Construction Technology in Urban Rail Transit Beijing Urban Construction Design and Development Group Co.Ltd.Beijing 100037China Department of Civil Engineering Tsinghua UniversityBeijing 100084China Department of Civil and Environmental Engineering University of AlbertaEdmonton T6G2R3Canada UniversitéGustave Eiffel Département GERSLaboratoire Centrifugeuses Géotechniques(CG)Bouguenais 44341France

Experimental data taken from free-field soil in 1-g shaking table tests are valuable for seismic studies on soil-structure *** the available data from medium-to large-scale shaking table tests were not abundant enough to cover a large variety of types and conditions of the *** the study,1-g shaking table tests of a 3-m-height sand column were conducted to provide seismic experimental data about *** sand was directly collected in-situ,with the largest grain diameter being 2 cm and containing a water content of 6.3%.Properties of the sand were estimated under the influence of white noise plus pulse and earthquake motions,including the settlement,the dynamic properties of the sand column,and the three soil layers′shear modulus degradation *** estimated properties were then indirectly verified by means of finite element *** show that the estimated parameters were effective and could be used in numerical modeling to reproduce approximate seismic responses of the sand column.

关键词： 1-g shaking table test seismic sand response dynamic soil properties free-field sand

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Thermal and mechanical properties of bio-cemented quartz sand mixed with steel slag

Biogeotechnics

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Biogeotechnics 2023年第3期1卷 44-51页

作者： Shuang Li Ming Huang Mingjuan Cui Kai Xu Guixiao Jin College of Civil Engineering Fuzhou UniversityFuzhou 350108China College of Ecological Environment and Urban Construction Fujian University of TechnologyFuzhou 350118China

The aim of this study is to disclose the feasibility of improving the thermal conductivity and mechanical strength of quartz sand steel slag mixtures treated by enzyme-induced carbonate precipitation(EICP).In this work,the effects of steel slag content(SSC)and number of treatment cycle(N)on the thermal conductivity and mechanical strength of EICP-treated specimens were *** immersion method was adopted for specimen *** thermal conductivity was measured by transient plane source method(TPS)and the unconfined compressive strength(UCS)was obtained through a uniaxial compression ***,the SEM test was conducted to obtain the morphology and deposition characteristics of calcium carbonate *** result shows that the thermal conductivity and UCS of EICP-treated sands increase before decreasing as the SSC ***,the maximum values of thermal conductivity and UCS are 1.28 W/(m⊡K)and 6.31 MPa,respectively,corresponding to the optimal parameter of 20%SSC at 12 *** optimal thermal conductivity and UCS increase by 367%and 137%,respectively,compared to that of EICP-treated sand with no addition of steel *** SEM analysis indicates that the spherical calcium carbonate exists in the range of 0-20%SSC,whereas there is mainly amorphous calcium carbonate when the SSC varies from 40%to 80%.It also demonstrates that the UCS is more sensitive to the variation of calcium carbonate content than that of thermal conductivity.

关键词： Enzyme-induced carbonate precipitation (EICP) Steel slag Quartz sand Thermal conductivity Unconfined compressive strength(UCS)

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Untangling the Complexities of the Uptake of Smart construction Sites in South Africa 20th

Untangling the Complexities of the Uptake of Smart Construct...

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20th International Conference on Computing in civil and Building engineering, ICCCBE 2024

作者： Ikuabe, Matthew Aigbavboa, Clinton Ngcobo, Ntebo Aghimien, Lerato cidb Centre of Excellence Faculty of Engineering and the Built Environment University of Johannesburg Johannesburg South Africa Department of Civil Engineering Technology Faculty of Engineering and the Built Environment University of Johannesburg Johannesburg South Africa Department of Construction Management and Quantity Surveying Faculty of Engineering and the Built Environment University of Johannesburg Johannesburg South Africa School of Construction Economics and Management Faculty of Engineering and the Built Environment University of the Witwatersrand Johannesburg South Africa

ISBN: (纸本)9783031842078

Using technological applications, smart construction aims to improve the planning, management, and execution of construction project delivery. This has the potential to forestall several of the challenges associated with project execution and delivery using conventional methods. Therefore, this study evaluates the challenges of implementing smart construction sites in the South African construction industry. Employing a quantitative technique, data was elicited from the target respondents who were sampled using convenience and snowball sampling techniques. Retrieved data was analysed using exploratory factor analysis using the principal component analysis extraction technique. The study’s findings showed that the significant challenges faced by implementing smart construction sites in South Africa are institutional drawbacks, financial impediments, and lack of technical expertise. The study contributes theoretically and practically to the growing call for construction digitalisation as it fills the gap in knowledge by unravelling the encumbrances of the use of smart construction sites. Furthermore, the study’s outcome is a sound theoretical base for future studies geared towards construction digitalisation in developing countries. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

关键词： Decentralized finance

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An improved analytical solution for solving the shield tunnel uplift problem

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Journal of Rock Mechanics and Geotechnical engineering 2024年第11期16卷 4570-4585页

作者： Bin Wang Jietao Li Chenyang Zhao Jun Wang State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China Guangdong Research Center for Underground Space Exploitation Technology School of Civil EngineeringSun Yat-sen UniversityGuangzhou510275China State Key Laboratory for Tunnel Engineering Sun Yat-sen UniversityGuangzhou510275China Jiangsu Provincial Transportation Engineering Construction Bureau Nanjing210004China

The problem of shield tunnel uplift is a common issue in tunnel *** to the decrease in shear stiffness at the joints between the rings,uplift is typically observed as bending and dislocation deformation at these *** modeling methods typically rely on the Euler-Bernoulli beam theory,only considering the bending effect while disregarding shear ***,the constraints on the shield tail are often neglected in existing *** this study,an improved theoretical model of tunnel floating is *** constraint effect of the shield machine shell on the tunnel structure is considered using the structural forms of two finite long beams and one semi-infinite long ***,the Timoshenko beam theory is adopted,providing a more accurate description of tunnel deformation,including both the bending effect and shear deformation,than existing ***,the buoyancy force and stratum resistance are calculated in a nonlinear manner.A reliable method for calculating the shear stiffness correction factor is proposed to better determination of the calculation *** proposed theoretical model is validated through five cases using sitemonitored *** applicability and effectiveness are ***,the influences of soil type,buried depth,and buoyancy force on the three key indicators of tunnel floating(*** maximum uplift magnitude,the ring position with the fastest uplift race,and the ring position with the maximum uplift magnitude)are *** results indicate that the proposed model can provide a better understanding of the floating characteristics of the tunnel structure during construction.

关键词： Analytical solution Conceptual model Matrix transfer method Shield tunnel Timoshenko beam theory Tunnel uplift

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Machine Learning Enhanced Boundary Element Method:Prediction of Gaussian Quadrature Points

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Computer Modeling in engineering & Sciences 2022年第4期131卷 445-464页

作者： Ruhui Cheng Xiaomeng Yin Leilei Chen College of Architecture and Civil Engineering Xinyang Normal UniversityXinyang464000China College of Intelligent Construction Wuchang University of TechnologyWuhan430223China School of Architectural Engineering Huanghuai UniversityZhumadian463000China

This paper applies a machine learning technique to find a general and efficient numerical integration scheme for boundary element methods.A model based on the neural network multi-classification algorithmis constructed to find the minimum number of Gaussian quadrature points satisfying the given *** constructed model is trained by using a large amount of data calculated in the traditional boundary element method and the optimal network architecture is *** two-dimensional potential problem of a circular structure is tested and analyzed based on the determined model,and the accuracy of the model is about 90%.Finally,by incorporating the predicted Gaussian quadrature points into the boundary element analysis,we find that the numerical solution and the analytical solution are in good agreement,which verifies the robustness of the proposed method.

关键词： Machine learning Boundary element method Gaussian quadrature points classification problems

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Effect of dry-wet cycles on dynamic properties and microstructures of sandstone:Experiments and modelling

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International Journal of Mining Science and technology 2024年第5期34卷 655-679页

作者： Hai Pu Qingyu Yi Andrey P.Jivkov Zhengfu Bian Weiqiang Chen Jiangyu Wu State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Earth Engineering China University of Mining and TechnologyXuzhou 221116China Key Laboratory of Xinjiang Coal Resources Green Mining Ministry of EducationXinjiang Institute of EngineeringUrumqi 830023China Department of Solids and Structures School of EngineeringUniversity of ManchesterManchester M139PLUK School of Environment Science and Spatial Informatics China University of Mining and TechnologyXuzhou 221116China Department of Civil and Environmental Engineering Rice UniversityHouston 77005USA State Key Laboratory of High Performance Civil Engineering Materials Jiangsu Research Institute of Building Science Co.Ltd.Nanjing 210008China Department of Materials University of OxfordOxford OX13PHUK

Underground pumped storage power plant(UPSP)is an innovative concept for space recycling of abandoned *** realization requires better understanding of the dynamic performance and durability of reservoir *** paper conducted ultrasonic detection,split Hopkinson pressure bar(SHPB)impact,mercury intrusion porosimetry(MIP),and backscatter electron observation(BSE)tests to investigate the dynamical behaviour and microstructure of sandstone with cyclical dry-wet damage.A coupling FEM-DEM model was constructed for reappearing mesoscopic structure *** results show that dry-wet cycles decrease the dynamic compressive strength(DCS)with a maximum reduction of 39.40%,the elastic limit strength is reduced from 41.75 to 25.62 *** sieved fragments obtain the highest crack growth rate during the 23rd dry-wet cycle with a predictable life of 25 cycles for each rock *** pore fractal features of the macropores and micro-meso pores show great differences between the early and late cycles,which verifies the computational statistics analysis of particle *** numerical results show that the failure patterns are governed by the strain in pre-peak stage and the shear cracks are *** dry-wet cycles reduce the energy transfer efficiency and lead to the discretization of force chain and crack fields.

关键词： Underground pumped storage power plant Dry-wet cycles Split Hopkinson pressure bar Macro and micro properties FEM-DEM coupling model Damage characterization

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Insulation effect on post-earthquake fire punching shear behavior of slab–column connections

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Asian Journal of civil engineering 2023年第7期24卷 2505-2520页

作者： Mohammed, Tesfaye Alemu Shirtaga, Shewarega Construction Quality and Technology Center of Excellence Addis Ababa Science and Technology University Addis Ababa Ethiopia Department of Civil Engineering Addis Ababa Science and Technology University Addis Ababa Ethiopia

This research work numerically investigates effect of insulation on the punching shear behavior of interior GFRP-reinforced slab–column connections under post-earthquake fire. Two experimental results reported in the literature were used for validation analysis using ANSYS nonlinear finite-element software program. Further, parametric studies on influential variables such as fire exposure duration, application of vermiculite gypsum insulation system, and use of GFRP stirrups around the slab–column connections were performed to get insight into performance gains of using insulation on post-earthquake fire behavior of GFRP-reinforced slab–column connections. Finite-element analysis results showed use of vermiculite gypsum insulation system improved the punching shear capacity of GFRP-reinforced slab–columns by 20.99%. Compared to the control, increasing the thickness of vermiculite gypsum insulation to 11 mm, 15 mm and 20 mm reduced heat transfer in a slab by 72.96%, 76.51% and 79.62%, respectively, whereas the unbalanced drift moment ratio was enhanced in ranges 20.14% to 20.99%. Use of vermiculite gypsum insulation system to improve post-earthquake fire shear behavior of GFRP slab–beam connection is recommended. © 2023, The Author(s), under exclusive licence to Springer Nature Switzerland AG.

关键词： Finite-element analysis Fire insulation Punching shear Slab–column connections

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RECREATION LAND USE IN TERMS OF WATER PROTECTION 14

RECREATION LAND USE IN TERMS OF WATER PROTECTION

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14th Conference on Public Recreation and Landscape Protection - With Environment Hand in Hand?

作者： Hlinkova, Maria Fijko, Rastislav Institute of Technology Economics and Management in Construction Faculty of Civil Engineering Technical University of Kosice Vysokoskolska 4 Kosice040 01 Slovakia Institute For Sustainable And Circular Construction Faculty of Civil Engineering Technical University of Kosice Vysokoskolska 4 Kosice040 01 Slovakia

ISBN: (纸本)9788075099051

The landscape has a wide range of uses. The current era encourages urbanism and rapid development of cities, but it is necessary to think and leave space for recreational use as well. The development of green spaces not only creates heat islands, but also degrades the recreational potential of the landscape. A vegetated environment is more pleasant to people than a concrete jungle. Water areas fulfil several functions, among which we can also include the recreational function. The use of water areas is also related to their protection. As more and more land is covered with impermeable surfaces, such as roads, buildings, and pavements, there is a reduction in the natural infiltration and percolation of rainwater into the soil. This results in increased surface runoff, which can cause flooding and erosion, and also leads to a decline in the groundwater recharge. Overall, the rapid pace of urbanization is taking a toll on the environment and its components. It is important to find ways to balance the need for development with the preservation of nature, in order to ensure a sustainable future. © 2023 Public Recreation and Landscape Protection - With Environment Hand in Hand? Proceedings of the 14th Conference. All rights reserved.

关键词： Land use

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A new theory for determining large deformation area of roof at intersection and verification analysis

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Journal of Central South University 2025年第2期32卷 656-677页

作者： WU Yi-yi GAO Yu-bing MA Xiang ZHANG Xing-xing HE Man-chao College of Construction Engineering Jilin UniversityChangchun 130026China State Key Laboratory for Tunnel Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Energy and Mining Engineering China University of Mining and Technology(Beijing)Beijing 100083China

The intersection is a widely used traffic line structure from the shallow tunnel to the deep roadway,and determining the subsidence hidden danger area of the roof is the key to its stability ***,applying traditional maximum equivalent span beam(MESB)theory to determine deformation range,peak point,and angle influence poses a *** the overall structure of the intersection roof,the maximum equivalent triangular plate(METP)theory is proposed,and its geometric parameter calculation formula and deflection calculation formula are *** application of the two theories in 18 models with different intersection angles,roadway types,and surrounding rock lithology is verified by numerical *** results show that:1)The METP structure of the intersection roof established by the simulation results of each model successfully determined the location of the roof’s high displacement zone;2)The area comparison method of the METP theory can be reasonably explained:①The roof subsidence of the intersection decreases with the increase of the intersection angle;②The roof subsidence at the intersection of different roadway types has a rectangular type>arch type>circular type;③The roof subsidence of the intersection with weak surrounding rock is significantly larger than that of the intersection with hard surrounding *** to the application results of the two theories,the four advantages of the METP theory are compared and clarified in the basic assumptions,mechanical models,main viewpoints,and mechanism *** large deformation inducement of the intersection roof is then *** J 2 peak area of the roof drives the large deformation of the area,the peak point of which is consistent with the center of gravity position of the ***,the change in the range of this peak is consistent with the change law of the METP’s ***,this theory clarifies the large deformation area of the intersection roof,which provides a clea

关键词： roadway intersection roof deformation equivalent span theory triangular plate structure numerical analysis stress partial tensor

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